A process optimization and release modeling of coaxial electrospun aligned core-shell poly (ethylene oxide-poly(l-lactide-co-glycolide)) nanofibers encapsulating nerve growth factor.

Recent advances in neural regeneration have demonstrated the importance of incorporating proteins into polymeric capsules to provide both topographical and biochemical cues to cells. Coaxial electrospinning has emerged as a versatile technique for embedding delicate bioactive agents within core-shell nanofibers, enabling controlled and sustained drug release. In this study, we employed a design-of-experiment approach to systematically investigate how controllable parameters in coaxial electrospinning influence the diameter and size distribution of aligned poly (ethylene oxide-poly(l-lactide-co-glycolide) nanofibers loaded with nerve growth factor (NGF).

Technology Roadmap for Flexible Sensors.

Humans rely increasingly on sensors to address grand challenges and to improve quality of life in the era of digitalization and big data. For ubiquitous sensing, flexible sensors are developed to overcome the limitations of conventional rigid counterparts. Despite rapid advancement in bench-side research over the last decade, the market adoption of flexible sensors remains limited.

Nanoparticle Rigidity for Brain Tumor Cell Uptake.

Nanoparticles (NPs) have emerged as versatile and widely used platforms for a variety of biomedical applications. For delivery purposes, while some of NPs' physiochemical aspects such as size and shape have been extensively studied, their mechanical properties remain understudied. Recent studies have reported NPs' rigidity as a significant factor for their cell interactions and uptake.

Direct Laser 3D Printing of Organic Semiconductor Microdevices for Bioelectronics and Biosensors.

Fabrication of conductive and bioactive microdevices has garnered tremendous attention in the emerging biomedical fields, particularly organic bioelectronics and biosensing. Direct laser 3D printing based on two-photon polymerization (TPP) has shown great promise in construction of well-defined and multi-functional microdevices. Herein, we present a novel photosensitive resin for fabrication of highly conductive and bioactive microstructures via TPP.

Multiphoton Lithography of Organic Semiconductor Devices for 3D Printing of Flexible Electronic Circuits, Biosensors, and Bioelectronics.

In recent years, 3D printing of electronics have received growing attention due to their potential applications in emerging fields such as nanoelectronics and nanophotonics. Multiphoton lithography (MPL) is considered the state-of-the-art amongst the microfabrication techniques with true 3D fabrication capability owing to its excellent level of spatial and temporal control. Here, a homogenous and transparent photosensitive resin doped with an organic semiconductor material (OS), which is compatible with MPL process, is introduced to fabricate a variety of 3D OS composite microstructures (OSCMs) and microelectronic devices.

Organic Semiconductor Nanotubes for Electrochemical Devices.

Electrochemical devices that transform electrical energy to mechanical energy through an electrochemical process have numerous applications ranging from soft robotics and micropumps to autofocus microlenses and bioelectronics. To date, achievement of large deformation strains and fast response times remains a challenge for electrochemical actuator devices operating in liquid wherein drag forces restrict the actuator motion and electrode materials/structures limit the ion transportation and accumulation. We report results for electrochemical actuators, electrochemical mass transfers, and electrochemical dynamics made from organic semiconductors (OSNTs).

Femtosecond Laser 3D-printing of Conductive Microelectronics for Potential Biomedical Applications.

Development of soft and conductive micro devices represents a demanding research topic in various biomedical applications, particularly organic bioelectronics. Among various fabrication methods, two-photon polymerization (2PP) using a wide range of photocurable inks is a promising 3D printing technique for construction of structures in submicron resolution. Herein, we introduce a novel conductive photosensitive resin by using poly (3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) and poly(ethylene glycol) diacrylate), and fabricate 3D conductive polymeric microstructures via 2PP.

Tumor Targeted Delivery of an Anti-Cancer Therapeutic: An In Vitro and In Vivo Evaluation.

The limited effectiveness of current therapeutics against malignant brain gliomas has led to an urgent need for development of new formulations against these tumors. Chelator Dp44mT (di-2-pyridylketone-4,4-dimethyl-3-thiosemicarbazone) presents a promising candidate to defeat gliomas due to its exceptional anti-tumor activity and its unique ability to overcome multidrug resistance. The goal of this study is to develop a targeted nano-carrier for Dp44mT delivery to glioma tumors and to assess its therapeutic efficacy in vitro and in vivo.

Conducting Polymer Microtubes for Bioactuators.

Conducting polymer (CP) actuators are promising devices for biomedical applications such as artificial muscles and drug delivery systems. Here, we report a tri-layer actuator based on poly(pyrrole) (PPy) microtubes (PPy MTs) doped with poly(sodium-p-styrenesulfonate) (PSS) and constructed on a passive layer of gold-coated poly-propylene (PP) film. The PPy MTs were fabricated using electrochemical deposition of PPy around poly(lactic-co-glycolic acid) (PLGA) fiber templates, followed by template removal.

Development and in vitro assessment of an anti-tumor nano-formulation.

This study aims to develop a new anti-cancer formulation based on the chelator Dp44mT (Di-2-pyridylketone-4,4-dimethyl-3-thiosemicarbazone). Dp44mT has outstanding anti-tumor activity and the unique ability to overcome multidrug-resistance in cancer cells. This highly toxic compound has thus far only been applied in free form, limiting its therapeutic effectiveness.

Electrospinning of Highly Aligned Fibers for Drug Delivery Applications.

Electrospinning is a straightforward, cost-effective, and versatile technique for fabrication of polymeric micro/nanofibers with tunable structural properties. Controlling the size, shape, and spatial orientation of the electrospun fibers is crucial for utilization in drug delivery and tissue engineering applications. In this study, for the first time, we systematically investigate the effect of processing parameters, including voltage, syringe needle gauge, angular velocity of rotating wheel, syringe-collector distance, and flow rate on the size and alignment of electrospun PLGA fibers.

Aligned Conducting Polymer Nanotubes for Neural Prostheses.

The long-term performance of neural microelectrodes relies on biocompatibility and sensitivity of the electrode-tissue interface. Current neural electrodes are limited by poor electrical performance including high initial impedance and low charge storage capacity. In addition, they are mechanically hard which causes cellular reactive response to the implanted electrode.

Direct Measurement of Mass Transport in Actuation of Conducting Polymers Nanotubes.

Nanostructured Conducting polymer (CP) actuators are promising materials for biomedical applications such as drug release systems. However, understanding the actuation behavior at the nano-scale has not yet been explored. In this work, poly(3,4-ethylenedioxythiophene) (PEDOT) and poly(pyrrole) (PPy) nanotubes doped with a large counter ion (i.

Tunable nanostructured conducting polymers for neural interface applications.

Advancement in the development of traditional metallic-based implantable electrodes for neural interfacing has reached a plateau in recent years in terms of their ability to provide safe, long-term, and high resolution stimulation and/or recording. The reduction of electrode size enables higher selectivity through increased electrodes per implant device; however, it also results in lower sensitivity at electrode-tissue interfaces. This limitation can be addressed through the utilization of conducting polymer (CP) coatings, which increase the effective surface area.

Conducting polymer microcontainers for biomedical applications.

Advancement in the development of metallic-based implantable micro-scale bioelectronics has been limited by low signal to noise ratios and low charge injection at electrode-tissue interfaces. Further, implantable electrodes lose their long-term functionality because of unfavorable reactive tissue responses. Thus, substantial incentive exists to produce bioelectronics capable of delivering therapeutic compounds while improving electrical performance.

Conducting Polymer Microcups for Organic Bioelectronics and Drug Delivery Applications.

An ideal neural device enables long-term, sensitive, and selective communication with the nervous system. To accomplish this task, the material interface should mimic the biophysical and the biochemical properties of neural tissue. By contrast, microfabricated neural probes utilize hard metallic conductors, which hinder their long-term performance because these materials are not intrinsically similar to soft neural tissue.

Conducting Polymers for Neural Prosthetic and Neural Interface Applications.

Neural-interfacing devices are an artificial mechanism for restoring or supplementing the function of the nervous system, lost as a result of injury or disease. Conducting polymers (CPs) are gaining significant attention due to their capacity to meet the performance criteria of a number of neuronal therapies including recording and stimulating neural activity, the regeneration of neural tissue and the delivery of bioactive molecules for mediating device-tissue interactions. CPs form a flexible platform technology that enables the development of tailored materials for a range of neuronal diagnostic and treatment therapies.

High performance conducting polymer nanofiber biosensors for detection of biomolecules.

Sensitive detection and selective determination of the physiologically important chemicals involved in brain function have drawn much attention for the diagnosis and treatment of brain diseases and neurological disorders. This paper reports a novel method for fabrication of enzyme entrapped-conducting polymer nanofibers that offer higher sensitivity and increased lifetime compared to glucose sensors that are based on conducting polymer films.

A review of organic and inorganic biomaterials for neural interfaces.

Recent advances in nanotechnology have generated wide interest in applying nanomaterials for neural prostheses. An ideal neural interface should create seamless integration into the nervous system and performs reliably for long periods of time. As a result, many nanoscale materials not originally developed for neural interfaces become attractive candidates to detect neural signals and stimulate neurons.

Hydrogel-mediated direct patterning of conducting polymer films with multiple surface chemistries.

A new methodology for selective electropolymerization of conducting polymer films using wet hydrogel stamps is presented. The ability of this simple method to generate patterned films of conducting polymers with multiple surface chemistries in a one-step process and to incorporate fragile biomolecules in these films is demonstrated.

Microencapsulation of chemotherapeutics into monodisperse and tunable biodegradable polymers via electrified liquid jets: control of size, shape, and drug release.

This paper describes microencapsulation of antitumor agent 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU, Carmustine) into biodegradable polymer poly(lactic-co-glycolic) acid (PLGA) using an electrojetting technique. The resulting BCNU-loaded PLGA microcapsules have significantly higher drug encapsulation efficiency, more tunable drug loading capacity, and (3) narrower size distribution than those generated using other encapsulation methods.

Conducting-polymer nanotubes improve electrical properties, mechanical adhesion, neural attachment, and neurite outgrowth of neural electrodes.

An in vitro comparison of conducting-polymer nanotubes of poly(3,4-ethylenedioxythiophene) (PEDOT) and poly(pyrrole) (PPy) and to their film counterparts is reported. Impedance, charge-capacity density (CCD), tendency towards delamination, and neurite outgrowth are compared. For the same deposition charge density, PPy films and nanotubes grow relatively faster vertically, while PEDOT films and nanotubes grow more laterally.